1. Field of the Invention
The present disclosure relates to an antibacterial imidazolium compound with excellent antibacterial performance over various strains, a photocurable coating composition comprising the same, and an antibacterial polymer coating prepared therefrom. Particularly, the antibacterial polymer coating maintains antibacterial activity for a long period of time after preparing it in an environmentally-friendly manner.
2. Background of the Invention
As human beings come into contact with objects, they may be infected by various diseases. Contagious bacteria may be spread through direct contact with human beings, but in most cases, human beings are infected by contagious bacteria such as virus indirectly as they come into contact with surface of objects which has been contacted by other people.
As density of population is high and a floating population is large, people come into contact with objects more frequently. Surfaces of doors, buses, handles of subways, desks, vending machines, public toilets, and the like, people are in contact in daily lives serve as mediums of transmitting bacteria unless they are sterilized each time.
Besides commonly used objects, cell phones, computer keyboards, pens, telephones, or the like of individuals may cause microbism. Thus, the development of antibacterial material that may be applied to household items or objects commonly contacted by various people is required.
Bacteria have different cell characteristics (e.g., Gram positive bacillus, Gram negative bacillus, aerobic bacteria, anaerobic bacteria), and various cell shapes such as a spherical shape, a plate shape, a cylindrical shape, an aggregate thereof, and the like. Thus, a polymer of antibiosis is required to have a function of impeding growth of various bacteria, as well as a single particular virus or germ. Thus, an antibacterial polymer aims at exhibiting a physical, chemical mechanism such as damaging a cell membrane/cell wall or degenerate protein or respiratory inhibition, and the like. Also, in many cases, an antibacterial material with respect to a particular germ does not exhibit antibacterial function with respect to a cell having a different structure, so the development of an antibacterial polymer material having generality is far-off.
Various types of antibacterial compounds or materials having a low molecular weight have been developed and used as antibacterial materials in various materials. In order to easily apply antibacterial materials to articles or in terms of cost, a method of coating only a target surface is a method for economically providing antibiosis to surfaces of a product, while maintaining intrinsic properties (mechanical, physical, chemical qualities, etc.) of objects.
In the case of various existing antibacterial materials, in most cases, antimicrobials are physically mixed in a matrix polymer (resin) so as to be used (e.g., an antifungal paint used by mixing antimicrobial in paint).
In antibacterial materials including antimicrobials, antibacterial compounds having a low molecular weight are leached and discharged over time; so the antibacterial function of the surfaces of products are reduced over time. Also, existing antimicrobials are generally used as additives; so an excessive amount, rather than appropriate amount, is used, and only a portion of the antimicrobials in use are positioned on the surface of a material to exhibit antibacterial function. So antimicrobials in use are limitedly utilized. In products in which antimicrobials are physically mixed to be added, effective antibacterial ingredients are reduced due to continuous cleaning and exposure and antibacterial activity is rapidly reduced as a service life thereof elapses. Also, the leached antimicrobials are exposed to the surrounding environment to contaminate water, soil, and the like, of the nature, causing a serious problem in the environment.
Thus, research into an antibacterial polymer material preventing antimicrobials from being leached in spite of the long-term use by chemically binding monomers having an antibacterial function to polymer chains has been conducted [A. Munoz-Bonilla, Prog. Polym. Sci., 37, 281 (2012); S. Jiang, Z. Cao, Adv. Mater., 22, 920 (2010); F. Rubmer, et al., Macromolecules, 42, 8573 (2009); E.-R. Kenawy, et al, Biomacromolecules, 8, 1359 (2007); S. D. Worley, TRIP, 4, 364 (1996); T. Tashiro, Macromol. Mater. Eng., 286, 63 (2001)].
In an antibacterial polymer material including an antibacterial treating group which are bonded thereto, the antibacterial treating agent exists in a state of being directly bonded to a polymer chain, so antibiosis is maintained although it is cleaned. Thus, it has high applicability with respect to clothes, bedding, and medical fiber products.
However, since the antibacterial polymer known so far has insufficient antibacterial activity and is mostly in a water soluble ammonium salt state, it is insoluble in an organic solvent and thus its application is not easy. Also, a material is water soluble or bonded to a surface of a product through a post-crosslinking reaction, which is, thus, not appropriate to be used as a coating material. Thus, the development of a reactive antibacterial monomer and a polymer material, which has excellent antibacterial activity, is economical, and is environmentally-friendly photocurable, so as to be easily coated on surfaces of construction interior materials, various electronic devices, household items, apparel product, packing materials, and containers for food by using a photocurable reaction, is required.